It looks like the Insteon integration is broken. I am seeing what appear to be incomplete dialogs when trying to create or modify an Insteon scene. I’ve uploaded a video to demonstrate the issue:
I wonder whether it is an issue with your theme? Or you need to clear your browser cache?
Well, I’m just using the ‘Default theme’ with the Dark option. No matter which option I use (Light, Dark or Auto) the result is the same. And I’ve accessed the Insteon integration from several different computers with identical results.